A conventionally known solenoid actuator is inserted through a mounting hole, which is formed in an outer wall of the engine, into an interior of the engine. Specifically, the solenoid actuator has an accommodated portion and the exposed portion. The accommodated portion is inserted into the interior of the engine. The exposed portion is other than the accommodated portion and is located outside the engine, such that the exposed portion is mounted onto an outer surface of the outer wall of the engine. The outer surface functions as a mounting surface. For example, Patent Document 1 discloses a solenoid actuator including an operation axis and a solenoid actuator portion. The operation axis is configured to bias one end of a spool of a hydraulic pressure control valve, which is equipped in an interior of an engine. The solenoid actuator advance and retreat the operation axis when energized and de-energized thereby to switch the hydraulic pressure control valve. The exposed portion of the solenoid actuator is equipped with a connector portion. The connector portion is connected with a wiring of the solenoid actuator. In general, the connector portion may be formed of resin in consideration of an electrically insulative property.
(Patent Document 1)
Publication of German unexamined patent application No. DE 10 2010 060 180 A1
An operator may remove a solenoid actuator from an engine for maintenance work or the like. In a case where an exposed portion of a solenoid actuator has a height in the axial direction enough, an operator may be enabled to hold an outer shell of the exposed portion steadily. It is noted that, the exposed portion of the solenoid actuator in Patent Document 1 may be in a flat shape to have a low height in the axial direction. Therefore, when an operator removes the solenoid actuator, which has the flat-shaped exposed portion, from an engine for a maintenance work and/or the like, the operator may hardly grip an outer shell of the flat-shaped exposed portion. Therefore, the operator may grip a connector portion projected from the exposed portion. Consequently, stress may be caused due to the weight of the solenoid actuator portion and/or the like, and the stress may be applied to the connector portion. Thus, the connector portion, which is formed of resin, may be damaged. In addition, a wiring connected to the connector portion may be disconnected. In addition, an operator may insert a tool into a clearance between the solenoid actuator and the engine and may wrench the solenoid actuator. Consequently, the main body of the solenoid actuator may be damaged. In a case where a main portion of the exposed portion is formed of resin, the main body may cause crack and/or breakage.